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llvm-project/llvm/test/CodeGen/AArch64/load-store-forwarding.ll

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[DAGCombiner] Fix for big endian in ForwardStoreValueToDirectLoad Summary: Normalize the offset for endianess before checking if the store cover the load in ForwardStoreValueToDirectLoad. Without this we missed out on some optimizations for big endian targets. If for example having a 4 bytes store followed by a 1 byte load, loading the least significant byte from the store, the STCoversLD check would fail (see @test4 in test/CodeGen/AArch64/load-store-forwarding.ll). This patch also fixes a problem seen in an out-of-tree target. The target has i40 as a legal type, it is big endian, and the StoreSize for i40 is 48 bits. So when normalizing the offset for endianess we need to take the StoreSize into account (assuming that padding added when storing into a larger StoreSize always is added at the most significant end). Reviewers: niravd Reviewed By: niravd Subscribers: javed.absar, kristof.beyls, llvm-commits, uabelho Differential Revision: https://reviews.llvm.org/D53776 llvm-svn: 345636
2018-10-31 04:16:39 +08:00
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc -mtriple=aarch64_be -o - %s | FileCheck %s --check-prefix CHECK-BE
; RUN: llc -mtriple=aarch64 -o - %s | FileCheck %s --check-prefix CHECK-LE
define i8 @test1(i32 %a, i8* %pa) {
; CHECK-BE-LABEL: test1:
; CHECK-BE: // %bb.0:
; CHECK-BE-NEXT: str w0, [x1]
; CHECK-BE-NEXT: ldrb w0, [x1]
; CHECK-BE-NEXT: ret
;
; CHECK-LE-LABEL: test1:
; CHECK-LE: // %bb.0:
; CHECK-LE-NEXT: str w0, [x1]
; CHECK-LE-NEXT: ret
%p32 = bitcast i8* %pa to i32*
%p8 = getelementptr i8, i8* %pa, i32 0
store i32 %a, i32* %p32
%res = load i8, i8* %p8
ret i8 %res
}
define i8 @test2(i32 %a, i8* %pa) {
; CHECK-BE-LABEL: test2:
; CHECK-BE: // %bb.0:
; CHECK-BE-NEXT: str w0, [x1]
; CHECK-BE-NEXT: ldrb w0, [x1, #1]
; CHECK-BE-NEXT: ret
;
; CHECK-LE-LABEL: test2:
; CHECK-LE: // %bb.0:
; CHECK-LE-NEXT: str w0, [x1]
; CHECK-LE-NEXT: ubfx w0, w0, #8, #8
; CHECK-LE-NEXT: ret
%p32 = bitcast i8* %pa to i32*
%p8 = getelementptr i8, i8* %pa, i32 1
store i32 %a, i32* %p32
%res = load i8, i8* %p8
ret i8 %res
}
define i8 @test3(i32 %a, i8* %pa) {
; CHECK-BE-LABEL: test3:
; CHECK-BE: // %bb.0:
; CHECK-BE-NEXT: str w0, [x1]
; CHECK-BE-NEXT: ldrb w0, [x1, #2]
; CHECK-BE-NEXT: ret
;
; CHECK-LE-LABEL: test3:
; CHECK-LE: // %bb.0:
; CHECK-LE-NEXT: str w0, [x1]
; CHECK-LE-NEXT: ubfx w0, w0, #16, #8
; CHECK-LE-NEXT: ret
%p32 = bitcast i8* %pa to i32*
%p8 = getelementptr i8, i8* %pa, i32 2
store i32 %a, i32* %p32
%res = load i8, i8* %p8
ret i8 %res
}
define i8 @test4(i32 %a, i8* %pa) {
; CHECK-BE-LABEL: test4:
; CHECK-BE: // %bb.0:
; CHECK-BE-NEXT: str w0, [x1]
; CHECK-BE-NEXT: ret
;
; CHECK-LE-LABEL: test4:
; CHECK-LE: // %bb.0:
; CHECK-LE-NEXT: str w0, [x1]
; CHECK-LE-NEXT: lsr w0, w0, #24
; CHECK-LE-NEXT: ret
%p32 = bitcast i8* %pa to i32*
%p8 = getelementptr i8, i8* %pa, i32 3
store i32 %a, i32* %p32
%res = load i8, i8* %p8
ret i8 %res
}